Superconducting instabilities of the non-half-filled Hubbard model in two dimensions
- Laboratoire de Physique des Solides, Universite Paris-Sud, 91405 Orsay (France)
The problem of weakly correlated electrons on a square lattice is formulated in terms of a one-loop renormalization group. Starting from the action for the {ital entire} Brillouin zone we reduce successively the cutoff {Lambda} about the Fermi surface and follow the renormalization of the coupling {ital U} as a function of three energy-momenta. We calculate the intrinsic temperature scale {ital T}{sub {ital co}} where the renormalization-group flow crosses over from the regime ({Lambda}{gt}{ital T}{sub {ital co}}) where the electron-electron ({ital e}-{ital e}) and electron-hole ({ital e}-{ital h}) terms are equally important to the regime ({Lambda}{lt}{ital T}{sub {ital co}}) where only the {ital e}-{ital e} term plays a role. In the low-energy regime only the pairing interaction {ital V} is marginally relevant, containing contributions from all renormalization-group steps of the regime {Lambda}{gt}{ital T}{sub {ital co}}. We identify the most attractive eigenvalue {lambda}{sub min} of {ital V}{sub {Lambda}={ital T}{sub {ital co}}}. At low filling, {lambda}{sub min} corresponds to the {ital B}{sub 2} representation ({ital d}{sub {ital xy}} symmetry), while near half filling the strongest attraction occurs in the {ital B}{sub 1} representation ({ital d}{sub {ital x}{sup 2}{minus}{ital y}{sup 2}} symmetry). In the direction of the van Hove singularities, the order parameter shows peaks with increasing strength as one approaches half filling. We also give a possible interpretation of angle-resolved photoemission spectroscopy experiments trying to determine the symmetry of the order parameter in the high-{ital T}{sub {ital c}} compound Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 383851
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 54, Issue 13; Other Information: PBD: Oct 1996
- Country of Publication:
- United States
- Language:
- English
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